Folding furniture structures of varying diverse constructions convertible between seating and bed configurations are well known and in widespread use, particularly for example so-called sofa sleepers or sofa bed structures having a frame mechanism movable between a folded condition suitable for seating use and an unfolded extended condition suitable for sleeping use. Apart from these general common characteristics, such convertible furniture structures employ many differing and varying forms of mechanical arrangements and also find equally diverse applications and end uses. For example, in addition to normal home usage of such convertible furniture, other common end use applications for convertible sofa bed or sofa sleeper structures are in vehicles, e.g., in recreational vehicles, campers, trailers and the like, and in hotels and motels, wherein space and utilitarian function can be at a premium. In particular, in such applications, the compactness of the overall structure and the ability of the mechanical arrangement to fold and unfold without requiring a clearance or spacing from an adjacent wall are desirable design features.